Peptide Biochemistry: Extracts of venom sacs from yellow jackets, hornets and wasps, as well as Gila monster venom contain peptides which have profound effects on human neutrophils and guinea-pig pancreatic acinar cells. The extracts inhibit enzyme release associated with neutrophil activation, they inhibit chemotaxis, and they can cause enzyme release. Extracts also cause the release of amylase from guinea-pig pancreatic acinar cells by mechanisms involving mobilization of cellular calcium and an increase in cellular cyclic AMP. The extracts are being fractionated by high performance liquid chromatography (HPLC) using a newly available column which gives separations superior to any we have obtained previously using other columns. A simple technique has been developed for rapidly desalting peptide solutions. To facilitate intra-laboratory reproducibility, a two-step gradient system has been developed as an alternative to our previously reported gradient system for the rapid analysis of amino acid phenylthiohydantoins. Several peptides have been coupled to chicken serum albumin and used to produce antibodies in burros and rabbits. Among the antibodies obtained it has been possible, for the first time, to produce antibodies against the aminotermini of bradykinin and angiotensin III.